The present invention relates to testing of one or more of multiple radio frequency (RF) data packet signal transceiver devices under test (DUTs) in a wireless signal test environment, and in particular, to enabling accurate block error rate (BLER) testing of LTE mobile devices in a wireless signal environment.
Many of today's electronic devices use wireless signal technologies for both connectivity and communications purposes. Because wireless devices transmit and receive electromagnetic energy, and because two or more wireless devices have the potential of interfering with the operations of one another by virtue of their signal frequencies and power spectral densities, these devices and their wireless signal technologies must adhere to various wireless signal technology standard specifications.
When designing such wireless devices, engineers take extra care to ensure that such devices will meet or exceed each of their included wireless signal technology prescribed standard-based specifications. Furthermore, when these devices are later being manufactured in quantity, they are tested to ensure that manufacturing defects will not cause improper operation, including their adherence to the included wireless signal technology standard-based specifications.
One common and widely used example of such devices is mobile, or cellular, telephone system that complies with the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standard, used for voice and data communications (e.g., sending and receiving of text messages, Internet browsing, etc.). Such devices are produced in large quantities and must be individually tested during manufacturing, as well as after the actual manufacturing process prior to final shipment and sale, in which case such testing must generally be performed in a radiative, or wireless, signal environment. One example of such end-of-line device testing is for uplink (UL) and downlink (DL) BLER testing (e.g., defined as a ratio of the sum of NACKs and the sum of ACKs plus NACKs).
When such a mobile device goes through a certification process, or end-of-line testing, with test instrumentation, important tests necessary to pass include UL and DL BLER and throughput. To achieve accurate test results, it is necessary to avoid circumstances under which data blocks are re-transmitted to overcome signal conditions producing failed data transmissions, whether in the UL or DL direction, since such repeated transmissions can mask device failures and/or faulty testing conditions, as well as increase test time.